1. Field of the Invention
This invention relates to spray-dried water-soluble vitamin powders which are directly compressible into tablets, and the powders prepared thereby. Particularly useful water-soluble vitamins are ascorbic acid, sodium ascorbate, and calcium ascorbate.
2. Description of the Prior Art
U.S. Pat. No. 3,293,132 describes a continuous process for making a vitamin C powder by spray drying. The process involves spray drying from 75 to 95 parts by weight of ascorbic acid, from 5 to 25 parts by weight of a carbohydrate, and from 0.5 to 5 parts by weight of a film-producing hydrophilic, organic colloid material such as gelatin, water-soluble derivatives of casein, water-soluble gums, and water-soluble derivatives of cellulose. Although the process is continuous, a lubricant is not one of the spray dried components. Instead, the lubricant is blended into the spray-dried powder after spray drying. Consequently, the powder taken directly from the spray dryer cannot be directly compressed into tablets. Moreover, the powder disclosed in this patent is likely to discolor at use conditions.